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- Nilforoush, Rasoul, et al.
(författare)
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Influence of Surface Reinforcement, Member thickness and Cracked Concrete on Tensile Capacity of Anchor Bolts
- 2017
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Ingår i: ACI Structural Journal. - : American Concrete Institute. - 0889-3241 .- 1944-7361. ; 114:6, s. 1543-1556
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Tidskriftsartikel (refereegranskat)abstract
- An extensive numerical study was carried out to evaluate the influence of concrete member thickness and orthogonal surface reinforcement on the tensile capacity and performance of anchor bolts in uncracked concrete members. Anchor bolts at various embedment depths (hef=50 to 300 mm (1.97 to 11.81 in.)) in unreinforced and reinforced concrete members of various thicknesses (H=1.5 – 5.0∙hef) were simulated. The reinforced concrete slabs were considered to be lightly-reinforced and over-reinforced to evaluate also the influence of amount of reinforcement. Furthermore, the behavior of anchor bolts at various embedment depths in pre-cracked reinforced concrete members was numerically investigated. The numerical results were compared with predictions from current design models including the Concrete Capacity (CC) method.The numerical results show that in uncracked concrete the tensile capacity of anchor bolts increases up to 20% and the anchorage behavior becomes more ductile with increasing member thickness or by having surface reinforcement. The numerical results also show that the CC method underestimates the tensile capacity of deep anchors (hef≥200 mm (7.87 in.)), while it slightly overestimates the capacity of short anchors (hef≤100 mm (3.94 in.)) in thin unreinforced members. It was also found that the over-reinforced concrete does not improve the anchorage capacity and performance any further than the lightly-reinforced concrete. Based on the numerical results, several recommendations are proposed to account for the influence of member thickness, surface reinforcement and cracked concrete. Further experimental studies are ongoing to verify and generalize the recommendations of this study.
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| 2. |
- Nilforoush, Rasoul, et al.
(författare)
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Tensile capacity of anchor bolts in uncracked concrete : Influence of member thickness and anchor’s head size
- 2017
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Ingår i: ACI Structural Journal. - : American Concrete Institute. - 0889-3241 .- 1944-7361. ; 114:6, s. 1519-1530
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the influence of concrete member thickness and size of anchor head on the tensile capacity and performance of anchor bolts in concrete. Anchor bolts at various embedment depths (hef=50 – 500 mm (1.97 – 19.69 in.)) in concrete members of various thicknesses (H=1.5 – 5.0∙hef) were simulated. Three different sizes of anchor head (small, medium and large) were considered at each anchor embedment depth. The numerical results were compared with predictions from several theoretical and empirical models, including current design models, as well as some test results.The numerical results show that the concrete cone resistance increases with increasing thickness of concrete member and/or size of the anchor head. Simulations also indicate that current design models generally underestimate the tensile capacity of large anchors.Two modification factors are proposed to account for the influence of the member thickness and the size of anchor head. Predictions of anchorage capacity using the proposed modification factors have good correlation with the available test results found in the literature.
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